function [ cdfx cdfy ] = cdf_function( data )
%CDF_FUNCTION 
sorted_data = sort(data);
indx=1;
cdfx(1) = sorted_data(1);
cdfy(1) = 1;%the probability of having the number at cdfx(1)
for i = 2:length(sorted_data)
    if sorted_data(i-1) == sorted_data(i);
        cdfy(indx) = cdfy(indx) + 1;
    else
        cdfy(indx+1) = cdfy(indx) + 1;
        cdfx(indx+1) = sorted_data(i);
        indx=indx+1;
    end
end
cdfy = cdfy/i;
plot(cdfx, cdfy );
end